Originally Posted by Johnf3
That's the poor man's supercharger, with the added bonus of hot, oily crankcase vapors. No better place for it then directly down the throat of the carb.
Kidding aside, lots of bikes, KTM's real dirt bikes w/ FCR carbs, for example, have their crankcase vent hoses attatched directly to the carb manifold. It works fine. In the case of the CPR set up shown in the picture, my preference was a bit of a cleaner less homemade look, so I just left it outside.
I get the sarcasm... There was some in my original post too.
I've built a bunch of race bikes, changed everything except for the air in the tires, and I've never ran the crankcase vent into the airbox. More often, I've ran it down to just above the countershaft so any hot oily water vapor lands on the chain doing it some good, or simply putting a high mounted filter on it to keep the critters and water crossings out... been known to just stuff some filter foam inside the tube and zip tie it to the frame.
Originally Posted by moto-treks
The stock configuration has the breather vented inside the air box so I'm guessing this is done so that reason. I'm sure it has something to do with EPA requirements too.
You can have the breather vented; 1) outside, 2) inside with hole directing the vapors to the intake or 3) inside with no hose. I thought I'd try inside with hose first. I may remove the hose and see what it looks like after a few hundred miles.
Correct, EPA. I'd at least dump the hose on the plate. Should you blow a water pump, these LC8's are known to chug that tasty looking chocolate milkshake mixture of emulsified oil, water and antifreeze up that hose... and right into your throttle body... which would make the whole thing suck much worse.